Range-finder.



Patented July 20 2 SHEETS-SHEET 1.

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ATTORNEYS W. H. M. CHRISTIE.

RANGE FINDER.

APPLICATION FILED PEB. 20, 1909.

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W. H. M. CHRISTIE.

RANG-E FINDER.

APPLICATION FILED FEB. 20, 1909.

Patented July 20, 1909.

2 SHEETS-SHEET 2.

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WILLIAM HENRY MAHONEY CHRISTIE, OF GREENWICH, ENGLAND.

RANGE-FINDER.

Speocaton of Letters Patent.

Application filed February 20, 1909.

Patented July 20, 1909.

serial No. 479,250.

To all whom t may concern:

Be it known that I, VILLIAM HENRY MA- HONEY CHRISTIE, a subject of the King of Great Brit-ain and Ireland, of the Royal Observatory, Greenwich, in the county of Kent, England, have invented new and usefulk Improvements in Range-Finders, of which the following is a specification.

My invention relates to range finders of the kind in which reflectors at each end of a base are employed, and more especially to range finders such as that described in the specification of British Letters Patent No. l12,404 A. D. 1886, granted to me, my present invention having for its object to improve suoli range finders and render them very readily adjustable and less liable -to become distorted by changes of temperature, or other causes, s0 that the indications of the range finders are more exact.

I will describe my invention with referencel to the accompanying` drawings.

Flgure 1 is a vertical longitudinal section, and Fig. 2 is a horizontal longitudinal section, of an improved range iinder made in accordance with my present invention. Figs. 3, 4 and 5 are transverse sections respectively taken on the lines A, B, Fig. 2; C, D, Fig. l; and E, F. Fig. 2.

In range finders of the aforesaid kind, as hitherto made, the base which carries the optical parts is liable to become distorted under the heat of the sun. To prevent this I use a hollow metallic base 1, to carry the optical parts upon its upper outer side, and I surround this base, and t-he parts carried by it, with any usual, or suitable, protective tube 2. The said hollow base 1 is made of aluminium, or other metal which is a good conductor of heat, and is preferably made with a flat upper side, or top, for the reception of the optical parts, and with a rounded, or angled, under part. Convenient forms, in cross section, for the said hollow base 1 are, for instance, a segment of a circle, as shown in the drawings, or a triangle, or other equivalent form, which will give the requisite lateral stiffness and facilitate the passage of heat from one side to the other by conduction and radiation. I prefer to make the said base 1 thicker, or stronger, at

the parts which are most liable to distortion by strain, or the action of gravity. This I may do by casting fins on it, as shown at 65. The base l is attached to the protective tube somewhat distorted under strain, or theaction of gravity. The said points of attachment may consist of two screws 5 (see Fig. 4) toward one end with the intervention of resilient devices, or buffers, and one screw 6, toward the other end, (see Fig. 1), these screws passing through enlarged holes in the outer tube 2, and also with a resilient device, or buffer, so as to absorb jars, or vibrations, and allow of relative movement under expansion and contraction. The re* silient devices, or buliers, at these points of attachment may conveniently be pads of rubber (7, 7 and 9) surrounding each screw and contained in a metal tube 10, and pads 8 situated between the base 1 and the inside of the protective tube 2, and between the outside of thel protective tube 2 and the head of each screw, 5 and 6, or a washer 11 thereon, as shown, and caps 12 may be placed, and secured, over the screw-heads as illustrated.

As the tube 2 is to protect the base 1 from unequal heating, for instance by the suns rays striking on one side, the said tube 2 should be made, as far as possible, or convenient, non-conductive of heat to the inside, while conductive of heat all around the tube, the air-space between the base 1 and the inside of the tube 2 insuring the base 1.

being equally subjected all around to any heat. The tube 2, for this purpose, is preferably made of aluminium, or other suitable metal, and, outside this, a layer 13, of material non-conductive of heat, such as asbestos, cork, or wool, for example, and a leather covering 14 outside this.

The openings 15 and 16 in the tube 2, through which the rays from the object enter each end of the instrument, may be provided with means for preventing access of rain and of the suns rays, so that they do not impinge on parts of the base 1 and thus cause distortion. This can be eected by shields, projecting from the sides of the instrument, and these may be made for example as foldable flaps 17, with springs to act on a squared part to hold them open and closed, as shown.

In order to support the mirrors 3 and 4, firmly and without risk of their being strain ed; andyet ment thereof, I mount them each orraf-sup:V- port 18 ,(seeuredteteatlieubaserelae between-e three pairs of points, two pairs at botto and one pair at top, the members of? pair being in line front and back. The

are marked 19. The pt )iiitys` 2n() 3317;. o e rl .l .a 14 .u on the front, opposite the points 19,:are ca images canbe easily separated, forobservatioin'of small objects, wit-hout a suitable yerticalline, such, for example,` as `a star, or light, at night, *or a stone by day. A

The object glasses are marked 27aud 28. The slidingarrangement for the obj ect glass 28 `is'preferably made so that it is pressed against'the end of the micrometerv screw 29, by springv pressure, and this may be done as follows 'The point of themicrometer screw i 2`Qbea`rson a piece 370 of agate,`or other hard substance', `('seeFig. 3) on the side ot' the cell S19-of the object-glass, whichcell` is` for1ned withlslides .32,"to slide in guides 33, secured to the base l, the saidh agate, or like, piece, BOfbeing; kept-topitsbearing on the end ot' the micrometenscrew 29 by springs 34, act.- ing onfpin's 35,"projec ting tromA each 'side of the cellv Blifthe lines or action ofthe springs Beton the4 pins 35' being` preferablyT vparallel with the axis of the micrometer screw 29,

and as near to its' bearing on the agate, or lik'egpiece 30 as possible. The slide 32 preterablyextends the' whole` or a considerable portiomotthe width ofV the base 1, and it is narrow compared withk'itslengthand the screw nut through which 'the micrometer screw 29works maybe slit, as 'at' 36,' and can beconnected by a vscrew 3T, to allow of taking up wear of the said nut and micrometer screw 2). To allow of more conveniently setting the head ot' the micrometer screw 29 to zero, I provide an additional disk 3S, with a scale to indicate parts of a rotation of the micrometer screw 29, keyed onto the body of' the micrometer screw 29, and provided with a head 39 for turning it. By the side of this Vdisk 3S is carried the scale disk 40, which is held to the micrometer screw 29 by being` pressed onto the disk 3S by a pinching nut 4I (preferably a ily-nut) through the .textlich tear oss the back? ve-rf v th f ",Xvtter lthis" ald-QA justfment.""the disks B8 andr l0 are'l clamped together: by the pinching nutet'andthe instrument is ready for use. The eye-piece and prisms at thecenter of the lengtlrot' the instrumentmay be of the ordinary, or anysuitable kind, and require no description; I have, inthe foregoing description, prei sumed that Ithe instrument is usedlwitlrthe base liorizo1ital,`and in the position illusf trat'edin thedrawings, but it may ofcourse be used in any other convenient position.

'In referring` to the upperv and lower parts in the claims I mean the position shown in t-he :drawings regardless of the position in whichthe rinstrument may be used.

Iclaimzl i 1."A Vrange finder, having a protective tube, a hollow metallic base mounted in the lower'partthereof by means which allow of movement ot' the said base `under expansion andcontractioin or distortion of the protect#y ive1 tube; together with optical devices for theV range tinder'carried lby thev upper 'part of the said'hollow. metallic base,Y 'l *il 2. Ani-ange finder having a protective tube,a hollowmetallic base mounted inthe lower Vpaitthereot by means which allow o'f movementot the said base under expansion and contraction, or distortion of the protect# ivef tube,A together witlroptical devicesft'or the range finder iarried by the upper 'part l he* said hollow metallic base, said lprotec ne tubev being made ot metal covered witha material non-conductiveof heat vand further 'covered witha leather covering. f" A 1angefinder ha ving a protective tube; ailio'llow metallic base 'mounted in the lower partthereof by means whichallowof more# ment ofthe said base under expansion rand contraction or distortion of the protective tube, together with optical devicesfor the range finder carried by the upper part of the said hollow metallic base, said base being strengthened at the parts most liable to distortion by strain, or the action of gravity.

4. A range iinder having a hollow metallic base with a flat upper part and a rounded under part,` a protective tube in the lower part of which said base is mounted by means which all-ow of movement of the said base under expansion and contraction or distorico rio

tion of the protective tube and optical devices carried by the upper part of said hollow metallic base.

5. A range finder having a hollow metallic base with a flat upper part and an angled under part, a protective tube in the lower part of which said base is mounted by means which allow of movement of the said base under expansion and contraction or distortion of the protective tube, and optical devices carried by the upper part of the said hollow metallic base.

6. In range finders, a protective tube, a hollow metallic base mounted in the lower part thereof, optical devices carried by the upper part of the said hollow metallic base and screw attachments for securing the said base to the said tube, with intervening` re` silient devices, substantially as hereinbefore described.

7. In range finders, a protective tube, a hollow metallic base mounted in the lower part thereof, and optical devices carried on the upper part of said base, the latter being secured to the said tube at three points by devices which allow of movement of the base under expansion and contraction or distortion of the protective tube, substantially as hereinbefore described.

8. In range finders, a protect-ive tube, a hollow metallic base carried within the salne together with optical devices and means for mounting` the same on saidbase, said optical devices including mirrors and said mounting means comprising, for each mirror, a support and springs both carrying three points bearing on the back and front of the mirror respectively, and means for adjusting the relative position of the said points, whereby the position of the mirror kmay be altered, substantially as hereinbefore described.

9. In range finders, a protective tube, a hollow metallic base carried within the same together with optical devices and means foi mounting the same on said base, said optical devices including mirrors and said mounting means comprising, for each mirror a support secured to the base, and carrying three points to bear on the back of the mirror and also springs extending, at the front, over the edges of the mirror and carrying points to bear on the front of the mirror in line with the points on the support and means for altering the relative position of the points carried by the support whereby the position of the mirror may be adjusted, substantially as hereinbefore described.

l0. In range finders, a protective tube, a hollow metallic base carried within the same and object glasses supported on said base, together with means for mounting and adj usting one of the object glasses on the base, the said means consisting of the combination of guides secured to the base and a cell for the object glass adapted to slide in the guides, a micrometer screw and springs in the base acting on the cell to keep it against. the point of said micrometer screw, substantially as hereinbefore described.

l1. In range finders, a protective tube, a hollow metallic base carried within the same, object glasses supported on said base, together with means for mounting and adjusting one of' the object glasses on the base, the said means consisting in a micrometer screw, a cell for the object glass having a bearing piece against which the oint of said screw bears, the said cell being provided with sliders running in guides secured to the base and with pins and springs bearing thereon. the said pins being on either side of said bearing piece on the object glass cell so that the line of action of the springs is parallel with the aXis of the micrometer screw, substantially as hereinbefore described.

l2. In range finders, a protective tube, a hollow base within the same and optical parts carried by said base in combination with a micrometer screw for adjusting one of the optical parts and two disks mounted on said screw and marked with the requisite scales, one disk being fiXed to the micrometer screw, and provided with a turning head, and the other disk being capable of independent adjustment, on said screw, together to the fixed disk whereby the said disks can be operated separately for setting the range finder and then be clamped together for use, substantially as hereinbefore described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM HENRY MAHONEY CHRISTIE.

Witnesses:

CHARLES W. CRooKER, HERBERT D. JAMESON. 

